1/2 cup rendered bacon fat or vegetable oil or a combination
2 tablespoons water
Preheat the oven to 350°F. Grease a 9” square pan with bacon fat or vegetable oil.
Cook the bacon in a large heavy skillet over medium heat, stirring occasionally, until crisp and browned, about 8 minutes. Transfer the bacon with a slotted spoon to paper towels to cool. Reserve bacon fat for brownies in a measuring cup and add enough vegetable oil to measure 1/2 cup.
Stir together the brown sugar, flour, cocoa powder, and salt in a large bowl. In a separate bowl, whisk together the eggs with the 1/2 cup bacon fat, and water. Stir the liquid mixture into the dry mixture until combined. Pour batter into prepared pan, spreading it evenly. Sprinkle the reserved bacon over the batter.
Bake until set and a wooden pick inserted into the brownies comes out with only a few crumbs clinging to it, about 25 minutes. Let cool to room temperature, then cut.